8792b557eb
[ Upstream commit 8a2e4d37afb8500b276e5ee903dee06f50ab0494 ] Symptom: When the hsuid attribute is set for the first time on an IQD Layer3 device while the corresponding network interface is already UP, the kernel will try to execute a napi function pointer that is NULL. Example: --------------------------------------------------------------------------- [ 2057.572696] illegal operation: 0001 ilc:1 [#1] SMP [ 2057.572702] Modules linked in: af_iucv qeth_l3 zfcp scsi_transport_fc sunrpc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nf_tables_set nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set nf_tables libcrc32c nfnetlink ghash_s390 prng xts aes_s390 des_s390 de s_generic sha3_512_s390 sha3_256_s390 sha512_s390 vfio_ccw vfio_mdev mdev vfio_iommu_type1 eadm_sch vfio ext4 mbcache jbd2 qeth_l2 bridge stp llc dasd_eckd_mod qeth dasd_mod qdio ccwgroup pkey zcrypt [ 2057.572739] CPU: 6 PID: 60182 Comm: stress_client Kdump: loaded Not tainted 4.18.0-541.el8.s390x #1 [ 2057.572742] Hardware name: IBM 3931 A01 704 (LPAR) [ 2057.572744] Krnl PSW : 0704f00180000000 0000000000000002 (0x2) [ 2057.572748] R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:3 PM:0 RI:0 EA:3 [ 2057.572751] Krnl GPRS: 0000000000000004 0000000000000000 00000000a3b008d8 0000000000000000 [ 2057.572754] 00000000a3b008d8 cb923a29c779abc5 0000000000000000 00000000814cfd80 [ 2057.572756] 000000000000012c 0000000000000000 00000000a3b008d8 00000000a3b008d8 [ 2057.572758] 00000000bab6d500 00000000814cfd80 0000000091317e46 00000000814cfc68 [ 2057.572762] Krnl Code:#0000000000000000: 0000 illegal >0000000000000002: 0000 illegal 0000000000000004: 0000 illegal 0000000000000006: 0000 illegal 0000000000000008: 0000 illegal 000000000000000a: 0000 illegal 000000000000000c: 0000 illegal 000000000000000e: 0000 illegal [ 2057.572800] Call Trace: [ 2057.572801] ([<00000000ec639700>] 0xec639700) [ 2057.572803] [<00000000913183e2>] net_rx_action+0x2ba/0x398 [ 2057.572809] [<0000000091515f76>] __do_softirq+0x11e/0x3a0 [ 2057.572813] [<0000000090ce160c>] do_softirq_own_stack+0x3c/0x58 [ 2057.572817] ([<0000000090d2cbd6>] do_softirq.part.1+0x56/0x60) [ 2057.572822] [<0000000090d2cc60>] __local_bh_enable_ip+0x80/0x98 [ 2057.572825] [<0000000091314706>] __dev_queue_xmit+0x2be/0xd70 [ 2057.572827] [<000003ff803dd6d6>] afiucv_hs_send+0x24e/0x300 [af_iucv] [ 2057.572830] [<000003ff803dd88a>] iucv_send_ctrl+0x102/0x138 [af_iucv] [ 2057.572833] [<000003ff803de72a>] iucv_sock_connect+0x37a/0x468 [af_iucv] [ 2057.572835] [<00000000912e7e90>] __sys_connect+0xa0/0xd8 [ 2057.572839] [<00000000912e9580>] sys_socketcall+0x228/0x348 [ 2057.572841] [<0000000091514e1a>] system_call+0x2a6/0x2c8 [ 2057.572843] Last Breaking-Event-Address: [ 2057.572844] [<0000000091317e44>] __napi_poll+0x4c/0x1d8 [ 2057.572846] [ 2057.572847] Kernel panic - not syncing: Fatal exception in interrupt ------------------------------------------------------------------------------------------- Analysis: There is one napi structure per out_q: card->qdio.out_qs[i].napi The napi.poll functions are set during qeth_open(). Since commit 1cfef80d4c2b ("s390/qeth: Don't call dev_close/dev_open (DOWN/UP)") qeth_set_offline()/qeth_set_online() no longer call dev_close()/ dev_open(). So if qeth_free_qdio_queues() cleared card->qdio.out_qs[i].napi.poll while the network interface was UP and the card was offline, they are not set again. Reproduction: chzdev -e $devno layer2=0 ip link set dev $network_interface up echo 0 > /sys/bus/ccwgroup/devices/0.0.$devno/online echo foo > /sys/bus/ccwgroup/devices/0.0.$devno/hsuid echo 1 > /sys/bus/ccwgroup/devices/0.0.$devno/online -> Crash (can be enforced e.g. by af_iucv connect(), ip link down/up, ...) Note that a Completion Queue (CQ) is only enabled or disabled, when hsuid is set for the first time or when it is removed. Workarounds: - Set hsuid before setting the device online for the first time or - Use chzdev -d $devno; chzdev $devno hsuid=xxx; chzdev -e $devno; to set hsuid on an existing device. (this will remove and recreate the network interface) Fix: There is no need to free the output queues when a completion queue is added or removed. card->qdio.state now indicates whether the inbound buffer pool and the outbound queues are allocated. card->qdio.c_q indicates whether a CQ is allocated. Fixes: 1cfef80d4c2b ("s390/qeth: Don't call dev_close/dev_open (DOWN/UP)") Signed-off-by: Alexandra Winter <wintera@linux.ibm.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://lore.kernel.org/r/20240430091004.2265683-1-wintera@linux.ibm.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
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Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.